Taming complexity. Duhem pathway to Thermodynamics

My research will focus on some specific features of Duhem’s physics: • The new conceptual link between mechanics and thermodynamics, • The attempt at explaining the complexity of the physical world. I have tried to follow the intellectual pathway which led Duhem from an original interpretation of thermodynamics to a great plan for building up a physics of “qualities”. Two reasons have led me to focus on the decade 1886-1896. In the first place, I have found that the main and most ingenious concepts of Duhem’s physics were accomplished before the turn of the century. In the second place, I would like to stress that those remarks were put forward before the best known transformations experienced by the physical sciences around the turn of the century. The study of his physics is demanding, because quite sophisticated are both conceptual and mathematical components of his theories. Some issues he raised, in particular the complexity of the physical world, did not attracted his contemporaries; only after some decades, in the second half of the twentieth century, complexity would have met the interest of physicists. Moreover, he dignified the tradition of Aristotle’s physics, a tradition which had been looked upon as regressive with regard Galileo’s new science. He revived the ancient Greek meaning of the word “physics”: not only science of local motion, but a general theory of material transformations, encompassing contemporary physics, chemistry and perhaps some aspects of sciences of life. Galileo’s science had to fight against the old physics of qualities, in order to establish itself: the complexity of the physical world had to be neglected in favour of a simplified world. Duhem believed that, at the end of the nineteenth century, he could go back to that neglected world and carry it into the wider boundaries of a generalized Mechanics-Thermodynamics.